Arrangement of labyrinth packing for a rotary type of fluid-pressure apparatus



May 15, 1951 T. CLARK ETAL ARRANGEMENT OF LABYRINTH PACKING FOR A ROTARY TYPE.

OF FLUID-PRESSURE APPARATUS Filed Jan. 17, 1947 I I I I I I I I I I I I I I I I I I I IN VEN TORS Patented May 15, 1951 ARRANGEMENT OF LABYRINTH PACKING FOR A ROTARY TYPE OF FLUID-PRES- SURE APPARATUS Thomas Clark and John Harry Clapham Atkins,

. Coventry, England, assignors to Armstrong Sid- ,deley Motors Limited, Coventry, England Application January 1'7, 1947, Serial No. 722,706 In Great Britain December 9, 1946 4 Claims.

This invention relates to a rotary type of fluidpressure apparatus, such as a compressor or, internal-combustion or other turbine, and particularly one intended to operate, with. a-relatively very high linear speed of the radially-outer portions ofthe rotor.

' Our main object is to provide a labyrinth packing means which will serve in a satisfactory manner forbalancing the axial thrust on the rotor to a greater or less extent. I

According to the invention, a labyrinth packing, for a rotary type of fluid-pressure apparatus, includes a series of axially-spaced annular discs inten-acting between the stator and a ring to provide a tortuous passage for the fluid-pressure, and the ring is rigidly supported from the rotor of the apparatus by a pair of supporting discs fast with the rotor, at least one of the supporting discs being a cone-like disc arranged concavely to the other.

In a preferred arrangement the rotor is a ring or drum, and the supporting discs are shrunk on to it, or similarly mounted upon it, being axially located upon it and having intermeshing driving dogs, while one of them also has driving dogs which intermesh with driving dogs fast (directly or indirectly) with the drum. For preference the supporting discs are of high tensile steel, and the drum of a steel having a high thermal expansion characteristic, so that the radial fit will be maintained in working conditions between the supporting disc and the drum.

The single figure of the accompanying drawings is a fragmentary sectional elevation of part of an axial-flow compressor fitted, at its delivery end, with a labyrinth packing means according to the invention.

The drawing shows a rotor drum H having fast thereon pairs of opposed cone-like discs l2, as disclosed in the specification accompanying U. S. Patent Application Serial No. 709,644,, filed December 13, 1946, now U. S. Patent No. 2,497,151, dated February 14, 1950, in the names of the present applicants. The flow through the compressor is in the direction of the arrow I3, the stationary compressor blades, between the rows of rotor blades I4, being omitted for the sake of simplicity. The inner wall of the passage for the air is completed by means of rings I 5 disposed between the roots 16 0f the blades I4 of each row.

The labyrinth packing, which is disposed at the output end of the compressor, comprises a number of axially-spaced annular discs I! which in this instance are shown as being carried by a stator ring 18 to which their radially-outer ends 2 are secured by rivets, one of which is shown at I9. In the present instance the said stator ring I8 is shown as being built-up of a plurality of rings between which the various labyrinth discs I? are held in axially spaced relation, the individual stator rings and labyrinth discs being secured to one another by the aforesaid rivets IS. The ring I8 is formed with an inwardly extending flange 31 by which it is secured in position by means of bolts one of which is shown at 32. The discs IT project radially-inwardly to differ ent extents, and their inner peripheries coact with a correspondingly-stepped surface 20 of a ring 2 I. It will be understood, however, that the annular discs ll could alternatively becarried by the ring 2|, their external peripheries projecting radially to difierent extents and coacting with a correspondingly-stepped surface on the stator ring l8. Alternatively, some of the annular discs l'l could be carried by the ring 2| and others by the stator ring I8.

The ring 2| in this instance has a flange 22 riveted to the outer edges of a pair of cone-like supporting discs 23, 24 which are arranged concavely to one another, the disc 23 having relatively-slight conicity (i. e. being almost flat) compared with the disc 24. The discs 23, 24 are fast with the rotor l I, and in the present instance they are shown as being carried by a drum or flanged ring 25 which is bolted to the rotor drum I I, one of the bolts being shown at 26. The ring 25 may be of a material having a high thermal expansion characteristic, the discs 23, 24 being of high tensile steel, and they may be shrunk on to the periphery of the ring 25. The ring 25 provides axial location for the disc hubs, and, in addition, these are fitted with intermeshing driving dogs, as shown at 21, whilst the disc 23 carries dogs, as shown at 28, engaged by dogs, as shown at 29, on the hub of the adjacent disc l2 of the compressor.

The labyrinth packing acts in a known manner to reduce leakage of pressure, and the output pressure of the compressor is available against the appropriate face of the disc 23, tending to force this axially towards the left-i. e., biasing the rotor ll axially in the opposite direction to that in which it is biased by the-reaction of the rows of blades M from the fluid passing through the compressor. The construction is one which is well able to withstand this pressure without distortion. Thus, the thrust bearings for the rotor are relieved to a greater or less extent.

What we claim as our invention and desire to secure by Letters Patent of the United States i 1. In combination, a rotor of a steel having a high thermal expansion characteristic, a stator,

said rotor and stator:- forming. enacting parts of,

effect a peripheral seal with; the other,; a; pair of supporting discs for said' ring, at least one of said supporting discs being cone-like and arranged concavely to the other, Said uppering discs being of high tensileesteeland: forming.-

an end wall of a pressure fluid space-within said:

plant, the outer side of said: wall being exposed; to a considerably lower pressure than that'oii said pressure fluid, and means relatively-nonrotatively supporting said discs from said-rotor;

said means including a clamping ring detachabl-y seauredto th d cen nd, of the or: and; hari azan outw rd ra flan o ax a y en! seein aihub p rtio i the axia yut r n f. sa d; suppor dis s;

2'..,FQr use with rotary type of fluid pressure appara us ha in a t r and a en, a ator rin ar ed y sa d s at d s a r e y id rotoria; r tor r n ar ied out the p phery QF'SQJQ dis s, a labyrinth packi e w n s d.

stator; ring and rotor ring comprising axially spaced annular; members secured to one of said r n s ndmeans r supportin and axially compressing said; laybrinth, packing carried, by one of; said; rings, supppltt means; between said discs and; rotor; saidsupport means being of, a steel av g; hi h erm l e n ns n aracteristic,

whereby in operation when hot fluids are passed over the rotor said support means will be expanded radially outwardly thereby compressing and assuring a tight fit between the rotor and stator rings and, the labyrinth packing therebewe n, a d mea s for curin sa disuenort means to said rotor for rotation therewith.

3. A device as claimed in claim 2 characterised by the fact that said rotor ring is provided with a-plural-ity: oi; axially stepped faces about the;- periphfiif-y. for" registering successfully with saidmembers which are carried by the stator ring;v

4;.A3LdfifllQQ3SLG1fii-Hl6d in claim 3 characterised byithe facththatrthe members of the labyrinth packing are pIQViQQd with stepped walls from the; axiakmedialradial inner portion.

THOMAS CLARK. JOHN HARRY CLAPHAM ATKINS.

REEEREN ES L' PED The following" references: are of: record in: the file: 1 of" this 1 patent :1

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